Contamination control mats are common in medical, nuclear, and semiconductor chip manufacturing applications and also in waste removal applications such as asbestos abatement. Such mats are distributed by companies such as American Scientific Products under the trademark MICRO-CLEAN and Liberty Industries under the trademark TACKY MAT. The mats are placed on the floor on one side of a door way to a clean room, for example, for removing particulate matter from shoes and from wheels on carts, etc.
The mats are formed of rectangular layered sheets of plastic adhered to one another. Each sheet has an adhesive coated over the top thereof for adhering to the smooth side of the sheet immediately above it. The bottom sheet has an adhesive coat for adhering the mat to the floor. A protective sheet covers the top sheet of the mat until it is ready for use, when it is removed to expose the adhesive on the first sheet of the mat. The adhesive removes and binds any lose particulate matter on footwear as people walk across the mat. When the top-most sheet becomes contaminated, the sheet is removed to expose a new, adhesive coated sheet. A mat may have 20 or 40 individual sheets. Contamination control mats are referred to in U.S. Pat. Nos. 4,107,811, 4,143,194 and 4,559,250.
Removal of a contaminated sheet from the mat is easier where one or more corners of the sheet is not adhesive. A thin film may be placed over the adhesive on the corner so that the corner does not adhere to the adjacent layer. Alternatively, a corner of the mat may have the adhesive omitted from it entirely during the manufacturing process, thereby forming the non-adhesive corner. A sheet is removed by lifting one or more corners of the sheet and peeling the sheet back. The actual removal of the sheet can be done in several ways, depending on the practice of the person removing the sheet. For example, the sheet can be removed in one quick movement and then wadded up and discarded. Alternatively, it may be wadded up as it is being removed.
Removal of the sheets by current methods causes vibrations in the sheet, causing particulate matter to be dislodged from the sheet and to become airborne. Wadding of the sheet may also produce "airbornes". Contamination of the technicians' hands and clothing is also possible from current methods of removal. In the medical industry, this contamination may be bacterial or viral contaminants getting into the technician's hands or clothing. In the nuclear industry, this contamination will be radioactive particles. Moreover, because of the wadding of the sheets, contaminated sheets take up a significant volume for disposal. Removal of sheets by hand may also result in tearing of the sheet if, for example, there are defects in the sheet.
There is a need for a mat configuration and an apparatus and method for removing separate sheets of contamination control mats which allows removal and disposal of contaminated sheets in a more effective and efficient manner.